1. Technical Field
The present invention relates to processing on special ink which generates special glossiness on a printed material.
2. Related Art
A printing apparatus performs printing by selecting an ink volume corresponding to input color data and printing the ink volume on a sheet or the like. Therefore, a method of color matching for selecting an optimum ink volume for the input color data has been disclosed (for example, see, JP-T-2007-511175 and Japanese Patent No. 4388554).
Further, a printing apparatus using special ink which generates special glossiness on a printed material has been known. For example, such special ink contains a metal in addition to pigment. Therefore, appearance of a color of dots changes depending on the observation angles to the printed material so as to generate special glossiness.
When printing is performed by using the special ink, there arises the following problem in some cases. Contrast among different colors on the printed material is lower in comparison with a case where the special ink is not used and preferable texture of the printed material is not obtained for the following reason. That is, in the color matching, matching with the input color data is performed based on colorimetric values of inks. However, the calorimetric value of the special ink also changes depending on the observation angles. Therefore, a brightness difference is generated between the colorimetric value and actual color appearance in some cases. Accordingly, the contrast becomes lower on the printed material in some cases.